A new tribe, genus, and species of limnichid beetle, Wooldridge us perforatus, from Malaysia (Coleoptera: Limnichidae: W ooldridgeini)

A new tribe is established in the Limnichidae, Limnichinae, for a new genus and species, Wooldridge us perforatus, from Sabah, Malaysia. Two autapomorphic characters distinguish Wooldridgeini from the two other tribes ofthe subfamily Limnichinae; 1) the mesotarsus and metatarsus join their respective tibia ventrally (medially) and preapically instead of the usual apical only connection and 2) a large pore, presumed to be an opening of a prothoracic gland, is present on each hypomeron. Distinguishing characters are illustrated by scanning electron micrographs and line drawings. A key to the three tribes included in the Limnichinae is provided

Two new species of the aquatic beetle genus Macrelmis Motschulsky from Venezuela (Coleoptera: Elmidae: Elminae)

Two new species collected in northwestern Venezuela, Macrelmis milleri aneI M. hayelwe, are described and illustrated by line drawings and scanning electron micrographs. Both species are assigned to the new species group Macrelmis milleri, and characters of the new species group are described. A key to the species of the group is given

Joule Heating and Anomalous Resistivity in the Solar Corona

Recent radioastronomical observations of Faraday rotation in the solar corona can be interpreted as evidence for coronal currents, with values as large as $2.5 \times 10^9$ Amperes (Spangler 2007). These estimates of currents are used to develop a model for Joule heating in the corona. It is assumed that the currents are concentrated in thin current sheets, as suggested by theories of two dimensional magnetohydrodynamic turbulence. The Spitzer result for the resistivity is adopted as a lower limit to the true resistivity. The calculated volumetric heating rate is compared with an independent theoretical estimate by Cranmer et al (2007). This latter estimate accounts for the dynamic and thermodynamic properties of the corona at a heliocentric distance of several solar radii. Our calculated Joule heating rate is less than the Cranmer et al estimate by at least a factor of $3 \times 10^5$. The currents inferred from the observations of Spangler (2007) are not relevant to coronal heating unless the true resistivity is enormously increased relative to the Spitzer value. However, the same model for turbulent current sheets used to calculate the heating rate also gives an electron drift speed which can be comparable to the electron thermal speed, and larger than the ion acoustic speed. It is therefore possible that the coronal current sheets are unstable to current-driven instabilities which produce high levels of waves, enhance the resistivity and thus the heating rate.Comment: Submitted to Nonlinear Processes in Geophysics as a contribution from the 7th International Workshop on Nonlinear Waves and Turbulence in Space Plasmas", Beaulieu, France, April 21-25, 200

Self-generated and externally driven current oscillations in n-GaAs

Experimental investigations of self-generated and externally driven non-linear current oscillations due to impact ionization of shallow impurities in n-type GaAs at low temperatures are presented. The regular relaxation oscillations which appear at the onset of breakdown are destabilized by a magnetic field normal to the epitaxial layer and multifrequency oscillations and chaotic fluctuations following the Ruelle-Takens-Newhouse scenario can be found. Driving the self-generated oscillations with an external periodic bias voltage quasiperiodicity, mode locking, interaction and overlap of mode locked resonances and period doubling can be observed depending on frequency and amplitude of the external force. The reconstructed return maps, recorded phase diagrams and Devil's staircase agree with theoretical predictions based on the circle map and give new evidence of the universality of the transition from quasiperiodicity to chaos

A checklist of the Limnichidae and the Lutrochidae (Coleoptera) of the world

A checklist of the world species of Limnichidae (35 genera, 345 species) and Lutrochidae (1 genus, 11 species) is presented. The author, year of publication and page number, synonyms, distribution by country, and a terminal bibliography are given for each genus and species. Biological information is also reviewed

Study of vortex boundary layer interactions Final report, period ending 26 Jun. 1966

Vortex-boundary layer interaction, and turbulent pipeflow at very low speed

A study of shock-associated magnetohydrodynamic waves in the solar wind

Three major topics were addressed, one theoretical and two observational. The topics were: (1) an attempt to understand the evolution of the large-amplitude magnetohydrodynamic (MHD) waves in the foreshock, using a nonlinear wave equation called the Derivative Nonlinear Schrodinger equation (henceforth DNLS) as a model, (2) using the extensive set of ISE data to test for the presence of various nonlinear wave processes which might be present, and (3) a study of plasma turbulence in the interstellar medium which might be physically similar to that in the solar wind. For these investigations we used radioastronomical techniques. Good progress was made in each of these areas and a separate discussion of each is given

Shock-associated plasma density fluctuations in the interstellar medium

Theories of diffuse shock acceleration of the cosmic rays that predict that there should be regions of intense Alfven waves both upstream and downstream of the shock front are considered. Observations of similar waves near solar system shock waves show that they produce substantial density fluctuations. Such density fluctuations might produce observable scattering of radio waves. Observations which searched for angular broadening or blurring of radio sources whose lines of sight pass close to or through supernova remnants are discussed. No definite cases of remnant-associated scattering are detected. However, the source CL 4, which is viewed through the Cygnus Loop supernova remnant, may be such an object and merits further observation

A sensitive magnetic balance for the direct measurement of skin friction drag

Sensitive magnetic balance for direct measurement of skin friction dra

What's Next After Work First: Workforce Development Report to the Field

Moving people into the workforce quickly may be the best first step to moving them out of poverty; but, by itself, rapid attachment is not likely to achieve the more important workforce development goals of enabling people to keep their jobs and leave poverty behind. This report explores the new challenges to building self-sufficiency brought about by the work first orientation of welfare reform, and the steps that practitioners, policymakers, and researchers may need to consider to keep their poverty alleviation strategies on track. The report includes descriptions of innovations in three key areas -- employer involvement, working with work first, and postemployment services -- which P/PV believes to be necessary to advance workforce development in the uncertain climate of welfare and education and training reform